1. Field of the Invention
This invention relates to a method of correcting the temperature of a semiconductor substrate, which is suitable for use during manufacture of a semiconductor integrated circuit device in a semiconductor manufacturing apparatus.
2. Description of the Related Art
A method of manufacturing a semiconductor integrated circuit device is not capable of directly measuring or controlling the temperature of a semiconductor wafer substrate during a manufacturing process. The temperature of the semiconductor wafer substrate is normally measured or controlled by a thermocouple placed in the vicinity of the semiconductor substrate. This temperature is generally different from an accurate substrate temperature and thus corrected by using, for example, a thermocouple embedded in the substrate. In a manufacturing process in a vacuum atmosphere, even in an operation for manufacturing a semiconductor integrated circuit, the difference between a reference temperature and the substrate temperature, used for process control, shows a tendency to greatly vary depending on variation in the structure of equipment, e.g., the thermal capacity of a wafer stage or the like in which a substrate and a reference thermocouple are embedded, the degree of adhesion between the two or the emissivity of the substrate or the like.
It is further known in a so-called cold wall-type manufacturing apparatus wherein the temperature around a substrate is low as compared with these temperatures, that a reduction in temperature due to thermal radiation from the substrate greatly depends on the temperature of a peripheral portion of the substrate so that the substrate temperature changes. Many techniques such as a chemical vapor deposition (CVD) method and a physical vapor deposition (PVD) method employed in the process of manufacturing the semiconductor integrated circuit device involve such a problem. These techniques show a problem in that thermal environments of the thermal capacity of the substrate's peripheral portion, etc. vary depending on their process throughput and differ from each other depending on between respective apparatuses or equipment. It is thus necessary to simply evaluate and manage the dependence on the process throughput and the difference between the respective apparatuses.
However, a problem arises in that since it is not easy from the viewpoint of the equipment to place the substrate with the thermocouple embedded therein in a predetermined wafer processing position, take out or extract a feedthrough of the thermocouple into the air from inside the manufacturing process equipment in the atmosphere under the reduced pressure and thereby measure the temperature of the substrate, the dependence on the process throughput and the equipment-to-equipment difference cannot be sufficiently grasped and managed. Therefore, this has caused a problem that the reliability of the process and process compatibility between the respective apparatuses are not sufficiently ensured.
Due to the differences in thermal conductivity and emissivity, the temperatures of the surfaces of an insulating film and a metal thin film formed over the semiconductor wafer substrate do not necessarily coincide with the temperature of the wafer substrate. A problem arises in that since the surface temperature of the substrate varies depending on a multilayer structure of the semiconductor integrated circuit device even in the same manufacturing process, process conditions change.